Deadlines make us all more effective. They motivate us and present a wall past which nothing more can occur. Their use on reality competition shows should emphasize this. Those that do not finish before typically only blame themselves for it – not the rules of the game itself.
Simultaneously, most of us delay work on something until the deadline comes into sight. “Why do today what can be delayed until tomorrow.” We generally do a good job of understanding our abilities and schedule well enough to not allow ourselves to get too far behind schedule against that vicious deadline.
However, there is the special case of when the starting point of a project is well past the time needed to work in a sane manner against the deadline. You can only work so much smarter. And then sometimes it’s your own, unintentional fault that there is not enough time to do the quality and level of work that you expect from yourself. In those situations it’s a matter of rolling up your sleeves and putting as much in as possible to achieve the best result you can.
If that happens more than just every now and then though it does reflect a process issue. Do you have a process issue with deadlines?